In the field of contact lenses, various factors must combine to yield a material that has appropriate characteristics. Oxygen permeability, wettability, material strength and stability are but a few of the factors that must be carefully balanced to achieve a useable contact lens. Since the cornea receives its oxygen supply exclusively from contact with the atmosphere, good oxygen permeability is a critical characteristic for any contact lens material. Wettability also is important in that, if the lens is not sufficiently wettable, it does not remain lubricated and therefore cannot be worn comfortably in the eye. The optimum contact lens would therefore, have both excellent oxygen permeability, and excellent tear fluid wettability.
Polysiloxane materials are useful materials for making contact lenses due to, among other properties, their excellent oxygen permeability. See U.S. Pat. Nos. 4,153,641 and 4,189,546. However polysiloxanes are generally hydrophobic. Certain hydrophilic functional groups may be attached to polysiloxane-containing monomers, or prepolymers to improve their wettability. See U.S. Pat. Nos. 4,260,725 and 4,259,467. However, many hydrophilic comonomers are known to be incompatible with the polysiloxane monomers in the monomer mix, and require the presence of solubilizers and compatibilizers for the monomer mixture properly polymerize. U.S. Pat. Nos. 5,321,108, 5,387,662 and 5,539,016 to Kunzler et al. teach fluorosiloxane-containing monomers having improved solubility in solvents such as N-vinyl pyrrolidone and N,N-dimethyl acrylamide.
In addition to oxygen permeability, wettability and compatibility requirements, contact lens materials must resist deposits. Some polysiloxane materials tend to accumulate deposits. Fluorinating certain polysiloxanes monomers is known to improve deposit resistance. See, for example, U.S. Pat. Nos. 4,440,918, 4,990,582, 4,954,587, 5,079,319 and 5,010,141.
Fluorinated polysiloxanes with useful properties for non-hydrogel contact lenses are disclosed in U.S. Pat. Nos. 4,810,764 and 5,142,009. It would be desirable to provide a hydrogel material containing fluorinated polysiloxanes that is useful as an ophthalmic lens material.